1. Field of the Invention
The present invention relates to a supercharger drive device for variable transmission of a supercharger driven by a combustion engine.
2. Description of Related Art
The supercharger connected with and driven by the combustion engine has such a tendency that if it is adjusted to be suitable for a low-to-medium speed region, the supercharged pressure (the amount of charged air) in a high speed region will increase too much, but if it is adjusted to be suitable for the high speed region the supercharged pressure in the low-to-medium speed region will become insufficient. The patent document listed below discloses the drive device operable to switch the supercharger, which is operatively linked with a transmission connected with the combustion engine, on or off in dependence of a gear shifting of the transmission. The drive device disclosed in the patent document has, however, been found having such a problem that the change gear ratio of the supercharger itself remains constant and is therefore insufficient.